A five-judge Supreme Court gave its unanimous decision in a dispute about Nama's status which arose after a journalist, Gavin Sheridan, sought information from it in 2010 under EU freedom to environmental information regulations.

Although Nama is obliged to act commercially, it is undoubtedly vested with special powers well beyond those which result from the normal rules applicable to relations governed by private law, Mr Justice Donal O'Donnell said on behalf of the court.

Nama was established under statute which confers upon it substantial powers including compulsory acquisition, enforcement, and to apply to the High Court to appoint receivers, he said.

Its establishment and operations were "a significant part" of the executive and legislative response to an unprecedented financial crisis, he said.

Nama's scope and scale was "exceptional" and, if it were not, it would be unable to carry out the important public functions assigned to it, he said.

Mr Sheridan had sought information in 2010 from Nama under a freedom the environmental information regulations.

When Nama refused, Mr Sheridan referred the matter to the Information Commissioner, Emily O'Reilly, who ruled in September 2011 Nama should be subject to such requests.

After Nama lost its High Court appeal against the Commissioner's ruling, it brought an appeal to the Supreme Court which has dismissed the appeal.

Nama said last night that it was studying the judgement.

The agency noted that the Supreme Court said that Nama's response to the request for information was understandable.

Nama also said the court acknowledged that it was "not surprising" it appealed the Information Commissioner's decision to the High Court.

"The Supreme Court held that while the basis of the Information Commissioner and High Court decisions was incorrect in finding against Nama, based on the recent European Fish Legal case, Nama is to be deemed a public body that is subject to the AIE regulations," it said.